Google posted ads on its search results over the weekend that hinted Apple will soon refresh its iMac, Mac mini and MacBook lines.

As first reported by the Mac enthusiast site AppleInsider, searches Saturday on the Dutch and Italian versions of Google for the phrases "imac," "mac mini" and "macbook" included Google AdSense ads -- the sponsored text advertisements that accompany most search results -- that indicated new models were available. The ads included links to Apple's Dutch and Italian online stores.

On Sunday, Computerworld confirmed that some of the reported AdSense advertisements were still available. As of Monday morning, however, the ads had been replaced with ones sporting generic copy.

On the Italian version of Google, for example, a search on Sunday by Computerworld for "imac" pulled up an AdSense ad that read, "Nuovo design, ancora piu sottile. Configura il tuo all'Apple Store." Translated into English, the line read: "New design, more subtle. Configure your Apple Store."

Searches repeated Monday pulled different advertisements. On the Dutch version of Google, a search for "macbook" today brought up an ad that simply said, "Ontdek de nieuwe MacBook. Gratis bezorging! Bestel vandaag (Translation: "Discover the new MacBook. Free Shipping! Order today.")

Rumors of an impending revamp of Apple's desktop iMac and Mac mini lines, and its lowest-priced MacBook, have been circulating for several weeks.

Two weeks ago, for instance, AppleInsider cited unnamed Taiwanese manufacturing sources who said that an iMac refresh was likely before the middle of October.

Ads posted over the weekend hint at of an Apple refresh. This Dutch-language ad, for example, reads, "The newest MacBook. Thinner, lighter and faster!"

Analysts have generally agreed that the iMac, which was last updated in May 2009 in what one expert called an "underwhelming" move, is in sore need of a new face job and price point. Others have said Apple needs to break from its high-priced, high-margin habit and play in the less-expensive notebook market -- where Windows-powered netbooks have grabbed a major chunk of the consumer business.

Stephen Baker, an analyst with retail research firm NPD Group, echoed those comments today. "I think we'll see a $799 MacBook and a $999 MacBook in the next few days," Baker said Monday. "I can't see how Apple wouldn't go there."

Apple's current low-end notebook is the white-cased MacBook, which lists for $999, and is slightly discounted online by others, such as Amazon, which sells the laptop for $978.

Apple frequently introduces new products or tweaked existing lines on Tuesdays, something that has fueled speculation that the company could unveil new iMac, Mac Mini and MacBook models as soon as tomorrow.

Although Apple has not sent invitations to analysts and reporters for a product announcement, the company does not always hold formal events when it refreshes hardware. Last May, for example, Apple simply issued a press release when it updated the iMac and Mac mini.

Any new systems would include Mac OS X 10.6, aka Snow Leopard, the operating system upgrade that Apple launched at the end of August.